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Message-ID: <478B8D54.7010400@gmail.com>
Date: Mon, 14 Jan 2008 17:27:00 +0100
From: Jiri Slaby <jirislaby@gmail.com>
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To: Cyrill Gorcunov <gorcunov@gmail.com>
CC: Paul Gortmaker <p_gortmaker@yahoo.com>,
       LKML <linux-kernel@vger.kernel.org>, Andi Kleen <ak@suse.de>,
       Alexey Dobriyan <adobriyan@gmail.com>
Subject: Re: [PATCH] driver: ip27-rtc - convert ioctl to unlocked_ioctl
References: <20080113203223.GA6723@cvg> <478A8131.9050500@gmail.com> <478A82AD.3070904@gmail.com> <aa79d98a0801131332w45d6e0e9r13e96b69e7e1b70@mail.gmail.com> <aa79d98a0801132238o72266a91p78ae3a0c1476607c@mail.gmail.com> <478B7C4A.5090903@gmail.com> <20080114153806.GA6639@cvg> <478B86DA.1010902@gmail.com> <20080114160745.GB6639@cvg>
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On 01/14/2008 05:07 PM, Cyrill Gorcunov wrote:
> Yes, process would be stopped, and not *just* stopped but could spend
> all his cpu time-slice in attempt to get spinlock (espec if set time is
> much longer than read), but if we use mutex here the process could just
> sleep instead of trying to get spinlock granted. Am I wrong? Or this is
> not worth to do it?

I would say no. It'll spin only for nanoseconds there.